Double valve constructed from unitary single valves

ABSTRACT

A double valve includes a first unitary valve assembly and a second unitary valve assembly. Each unitary valve assembly includes a first outlet port, a second outlet port, and a spool. A first pilot assembly and a second pilot assembly are coupled to the first unitary valve assembly and the second unitary valve assembly, respectively. A plate is coupled to the unitary valve assemblies and includes a passage to provide a first common outlet passage that is coupled to the respective first outlet ports of the unitary valve assemblies and a second common outlet passage that is coupled to the respective second outlet ports of the unitary valve assemblies. When the spools are in a first position, fluid flows through the first common outlet passage, and when the spools are in a second position, the fluid flows through the second common outlet passage.

BACKGROUND OF THE INVENTION

The present invention relates generally to a control valve, and morespecifically to a double valve constructed from two unitary valveassemblies.

Pneumatically powered machine tools operate through a valve system whichinteracts with a pneumatically controlled clutch and/or a brakeassembly. For safety reasons, control valves that operate the machinetools require the operator to simultaneously activate two separatecontrol switches to ensure that the operator's hands are away frommoving components of the machine tool when initiating an operatingcycle. An electronic circuit responsive to the two control switchesgenerates a pilot control signal applied to solenoid pilot valves tocontrol delivery of a fluid through the valve system to the machinetool.

In a typical 3-2 normally closed double valve, two movable valveassemblies are mounted within respective bores within a single valvebody. This is in contrast, for example, to a 3-2 normally open valve. Toachieve a normally-open function rather than a normally-closed function,the input and output pressures cannot simply be swapped. Rather, thecurrent state of the art is to use two separate valve assemblies in aparticular configuration to otherwise achieve a 3-2 normally openfunction. In one prior double valve, the solenoid pilot valves are movedto an actuated position in response to an electrical control signal froma respective operator-controlled switch, which allows fluid to flowthrough a single outlet passage of the double valve. If a valve assemblydoes not deactuate or actuate properly, or if the solenoid pilot valvesare actuated or deactuated non-simultaneously, the double valve canmalfunction. As the double valve includes a single outlet passage, thefluid can only be directed to a single location.

SUMMARY OF THE INVENTION

A double valve includes a first unitary valve assembly and a secondunitary valve assembly. Each unitary valve assembly includes a firstoutlet port, a second outlet port, and a spool. A first pilot assemblyand a second pilot assembly are coupled to the first unitary valveassembly and the second unitary valve assembly, respectively. A plate iscoupled to the unitary valve assemblies and includes a passage toprovide a first common outlet passage that is coupled to the respectivefirst outlet ports of the unitary valve assemblies and a second commonoutlet passage that is coupled to the respective second outlet ports ofthe unitary valve assemblies. When the spools are in a first position,fluid flows through the first common outlet passage, and when the spoolsare in a second position, the fluid flows through the second commonoutlet passage.

A pneumatically powered machine tool includes the above described doublevalve. When the unitary valve assemblies are in the first position, thefluid flows to a first end of a cylinder. When the unitary valveassemblies are in the second position, the fluid flows to a second endof a cylinder.

These and other features of the present invention will be bestunderstood from the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of the invention will becomeapparent to those skilled in the art from the following detaileddescription of the currently preferred embodiment. The drawings thataccompanies the detailed description can be briefly described asfollows:

FIG. 1 is a perspective view of a double valve;

FIG. 2 is an exploded perspective view of the double valve of FIG. 1;

FIG. 3 a is a side cross-sectional view of a 3/2 double valve in aninitial, deactuated position;

FIG. 3 b is a pneumatic circuit diagram showing the 3/2 double valve inthe deactuated position;

FIG. 4 a is a side cross-sectional view of the 3/2 double valve in anactuated position;

FIG. 4 b is pneumatic circuit diagram showing the 3/2 double valve inthe actuated position;

FIG. 5 a is a side cross-sectional view of the 3/2 double valve in anerrored and fail to safe position;

FIG. 5 b is a pneumatic circuit diagram showing the 3/2 double valve inthe errored and fail to safe position;

FIG. 6 a is a side cross-sectional view of the 3/2 double valve inanother errored and fail to safe position;

FIG. 6 b is a pneumatic circuit diagram showing the 3/2 double valve inthe another errored and fail to safe position;

FIG. 7 a is a side cross-sectional view of a double valve including 5/2unitary valve assemblies in an initial, deactuated position;

FIG. 7 b is a pneumatic circuit diagram showing the double valveincluding 5/2 unitary valve assemblies in the deactuated position;

FIG. 8 a is a side cross-sectional view of the double valve including5/2 unitary valve assemblies in an actuated position;

FIG. 8 b is pneumatic circuit diagram showing the double valve including5/2 unitary valve assemblies in the actuated position;

FIG. 9 a is a side cross-sectional view of the double valve including5/2 unitary valve assemblies in an errored and fail to safe position;

FIG. 9 b is a pneumatic circuit diagram showing the double valveincluding 5/2 unitary valve assemblies in the errored and fail to safeposition;

FIG. 10 a is a side cross-sectional view of the double valve including5/2 unitary valve assemblies in another errored and fail to safeposition;

FIG. 10 b is a pneumatic circuit diagram showing the double valveincluding 5/2 unitary valve assemblies in the another errored and failto safe position;

FIG. 11 a is a side cross-sectional view of double valve including 5/3unitary valve assemblies in an initial, deactuated position;

FIG. 11 b is a pneumatic circuit diagram showing the double valveincluding 5/3 unitary valve assemblies in the deactivated position;

FIG. 12 is a side cross-sectional view of the double valve including 5/3unitary valve assemblies in a first actuated position;

FIG. 13 is a side cross-sectional view of the double valve including 5/3unitary valve assemblies in a second actuated position;

FIGS. 14 to 19 are side cross-sectional views of the double valveincluding 5/3 unitary valve assemblies in various errored and fail tosafe positions;

FIG. 20 a is a side cross-sectional view of the double valve including5/2 unitary valve assemblies in an initial position;

FIG. 20 b is a pneumatic circuit diagram showing the double valveincluding 5/2 unitary valve assemblies in the initial position;

FIG. 21 a is a side cross-sectional view of the double valve including5/2 unitary valve assemblies in an actuated position;

FIG. 21 b is a pneumatic circuit diagram showing the double valveincluding 5/2 unitary valve assemblies in the actuated position;

FIG. 22 a is a side cross-sectional view of the double valve including5/2 unitary valve assemblies in an errored and fail to safe position;

FIG. 22 b is a pneumatic circuit diagram showing the double valveincluding 5/2 unitary valve assemblies in the errored and fail to safeposition;

FIG. 23 a is a side cross-sectional view of the double valve including5/2 unitary valve assemblies in another errored and fail to safeposition; and

FIG. 23 b is a pneumatic circuit diagram showing the double valveincluding 5/2 unitary valve assemblies in the another errored and failto safe position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate a double valve 10 including a first unitaryvalve assembly 11 and a second unitary valve assembly 12. The doublevalve 10 can be used with pneumatically powered machine tools thatoperate through a valving system which interacts with a pneumaticallycontrolled clutch and/or a brake assembly. In one example, the first andsecond unitary valve assemblies 11 and 12 are standard single valves. Apair of solenoid pilot valves 13 and 14 are coupled to the unitary valveassemblies 11 and 12, respectively, by adapter blocks 15 and 16,respectively. A first plate 17 is coupled to one side of both the firstand second unitary valve assemblies 11 and 12, and a second plate 18 iscoupled to an opposite side of the first and second unitary valveassemblies 11 and 12. Although the plates 17 and 18 are shown asseparate plates, it is possible that the plates 17 and 18 could becombined into a single plate. A pair of exhaust silencers 20 and 21 arecoupled to exhaust ports on the second plate 18 to muffle noise. Thefirst unitary valve assembly 11 includes an inlet port 22, an outletport 23, a first cross-mirror port 24, a second cross-mirror port 25,and an exhaust port 26. The second unitary valve assembly 12 includes aninlet port 27, an outlet port 28, a first cross-mirror port 30, a secondcross-mirror port 31, and an exhaust port 32. The first and secondunitary valve assemblies 11 and 12 are 5/2 way valves. Afterincorporation into the double valve 10, a 3/2-way valve is formed.

An inlet circuit contained in the first plate 17 includes inlet ports 33and 34, an inlet passage 35, and external inlet ports 36 and 37 atopposite ends of the first plate 17. The inlet ports 22 and 27 arecoupled to the inlet ports 33 and 34, respectively. An outlet circuitcontained in the first plate 17 includes outlet ports 38 and 39, anoutlet passage 40, and external outlet ports 41 and 59 at opposite endsof the first plate 17. The outlet ports 23 and 28 are coupled to theoutlet ports 38 and 39, respectively. As the first plate 17 includes twoinlet ports 33 and 34 and two outlet ports 37 and 38, one port can beused as a working port, and the second port can be used as a sensingport. For example, a pressure switch or a pressure transducer can beused to monitor the outlet pressure at the outlet port to function as asensing port.

The second plate 18 includes various internal passages for coupling withthe first and second unitary valve assemblies 11 and 12. The secondplate 18 includes a first cross-connection including ports 45 and 48interconnected by a cross-connection passage 55 for cross connecting thefirst cross-mirror port 24 of the first unitary valve assembly 11 withthe second cross-mirror port 31 of the second unitary valve assembly 12.The second plate 18 includes a second cross-connection including ports46 and 47 interconnected by a cross-connection passage 56 for crossconnecting the second cross-mirror port 25 of the first unitary valveassembly 11 with the first cross-mirror port 30 of second unitary valveassembly 12.

The second plate 18 also includes an exhaust circuit for interconnectingthe exhaust ports 26 and 32 of the first and second unitary valveassemblies 11 and 12, respectively. The second plate 18 includes exhaustports 50, 51, 52 and 53, and an exhaust passage 54 interconnects theexhaust ports 50 and 51 with the exhaust ports 52 and 53, respectively.The exhaust ports 50 and 51 are coupled to the exhaust ports 26 and 32of the first and second unitary valve assemblies 11 and 12,respectively. The exhaust ports 52 and 53 on the exterior side of thesecond plate 18 can be coupled to the exhaust silencers 20 and 21,respectively (shown in FIG. 1).

The second plate 18 includes pilot ports 57 and 58 coupled to thecross-connection passages 55 and 56, respectively, by other internalpassages (not shown). The pilot connections include a pair of tubes 60and 61 for supplying pilot pressure to the solenoid pilot valves 13 and14, respectively. A pair of elbow connections 62 and 63 couple the tubes60 and 61, respectively, to the pilot ports 57 and 58, respectively.Fittings 64 and 65 are coupled to connections 66 and 67, respectively,in the adapter blocks 15 and 16, respectively. The connections 66 and 67are coupled to passages 70 and 71, respectively, for supplying a sourceof pilot pressure to standard inlets in the solenoid pilot valves 13 and14, respectively. The passages 70 and 71 may also correspond with thepilot supply ports 72 and 73, respectively, on the first and secondunitary valve assemblies 11 and 12, respectively.

A pair of passages 74 and 75 in the adapter blocks 15 and 16,respectively, couple the output of the solenoid pilot valves 13 and 14,respectively, to the pilot passages 76 and 77, respectively, of thefirst and second unitary valve assemblies 11 and 12, respectively, toactuate the first and second unitary valve assemblies 11 and 12,respectively, when the corresponding solenoid pilot valves 13 and 14,respectively, are actuated by one or more electrical switches (notshown) to supply or remove a source of pressurized fluid. In oneexample, the fluid is pressurized air or hydraulic oil. In anotherexample, instead of using external tubings, pilot connections forsupplying pilot pressure to the solenoid pilot valves 13 and 14 caninclude internal passages within the bodies of the first and secondaryunitary valve assemblies 11 and 12, respectively, and/or within thesecond plate 18.

The second plate 18 also includes sensing ports 78 and 79 that areinterconnected with the cross-connection passages 55 and 56,respectively, by other internal passages (not shown) for providingsensing ports.

FIGS. 3 a to 6 b illustrate a first example double valve 10. The firstand second unitary valve assemblies 11 and 12 include spools 80 and 81,respectively, received in longitudinal bores 82 and 83, respectively, ofvalve bodies 84 and 85, respectively. The first and second unitary valveassemblies 11 and 12 are 5 port, 2 position valves (5/2-way valves)including inlet ports 86 and 87, respectively, outlet ports 88 and 89,respectively, exhaust ports 90 and 91, respectively, first cross-mirrorports 92 and 93, respectively, and second cross-mirror ports 94 and 95,respectively. The ports of the first and second unitary valve assemblies11 and 12 are interconnected by an inlet passage 35, an outlet passage40, an exhaust passage 54, a first cross-connection passage 55 (definedby the first cross-mirror port 92 and the second cross mirror port 89),and a second cross-connection passage 56 (defined by the firstcross-mirror port 93 and the second cross-mirror port 94). The firstplate 17 and the second plate 18 for implementing the passages 35, 40,54, 55 and 56 are not explicitly shown. The inlet passage 35, the outletpassage 40, and the exhaust passage 54 include external ports so theequivalent of a 3/2-way valve is achieved by the interconnection of thetwo 5/2-way unitary valve assemblies 11 and 12.

During operation, the double valve 10 is in an initial deactivatedposition. That is, during normal operation, fluid flows through thedouble valve 10. When both electrical switches actuate the correspondingsolenoid pilot valve 13 and 14, the double valve 10 is actuated,preventing the flow of the fluid through the double valve 10.

FIG. 3 a shows the double valve 10 in the deactuated position, and FIG.3 b shows a schematic representation of the pneumatic circuits of thedouble valve 10.

Pressurized fluid enters the double valve 10 through the inlet passage35 and from the inlet ports 86 and 87 is provided to the solenoid pilotvalves 13 and 14, respectively, via passages 96 and 97, respectively.Return resilient members 68 and 69 urge the spools 80 and 81 upwardly(with respect to FIG. 3 a). In one example, the resilient members 68 and69 are springs. The areas within the bores 82 and 83, respectively,under the spools 80 and 81, respectively, are coupled to the firstcross-mirror ports 92 and 93, respectively, via passages 43 and 44,respectively. The exhaust ports 90 and 91 are coupled to the secondcross-mirror ports 94 and 95, respectively. As the solenoid pilot valves13 and 14 are not actuated, fluid does not flow into the bores 82 and83; therefore, the bores 82 and 83 are not pressurized. The fluid flowsinto the inlet passage 35, flows through the inlet ports 86 and 87 tothe outlet ports 88 and 89, and exits the double valve 10 through theoutlet passage 40.

FIG. 4 a shows the double valve 10 in the actuated position, and FIG. 4b shows a schematic representation of the pneumatic circuits of thedouble valve 10. When the solenoid pilot valves 13 and 14 are actuatedby one or more electrical switches (not shown), a source of pressurizedfluid is supplied to actuate the double valve 10. When the double valve10 is actuated, the passages 96 and 97 are pressurized so that actuationof the solenoid pilot valves 13 and 14 pressurizes the bores 82 and 83,respectively, applying pressure to the spools 80 and 81, respectively,to move the spools 80 and 81, respectively, against the bias of theresilient members 68 and 69, respectively, to the actuated position, asshown in FIG. 4 a. In the actuated position, the spools 80 and 81 blockthe inlet ports 86 and 87, respectively, preventing the flow of fluidthrough the double valve 10. Fluid in the double valve 10 is exhaustedthrough the exhaust passage 54. For example, the pressurized fluid fromthe outlet passage 40 flows through the outlet ports 88 and 89,respectively, to the second cross-mirror ports 94 and 95, respectively,through the cross-connection passage 55 and 56, respectively, throughthe first cross-mirror ports 92 and 93, respectively, through theexhaust ports 94 and 95, respectively, and exits the double valve 10through the exhaust passage 54.

FIGS. 5 a and 6 a show the double valve 10 in errored and fail to safe,or “faulted,” positions, and FIGS. 5 b and 6 b, respectively, show aschematic representation of the pneumatic circuits of the double valve10 in the errored and fail to safe positions. In FIGS. 5 a and 5 b, thefirst unitary valve assembly 11 is in the deactuated position, and thesecond unitary valve assembly 12 is in the actuated position. In FIGS. 6a and 6 b, the first unitary valve assembly 11 is in the actuatedposition, and the second unitary valve assembly 12 is in the deactuatedposition.

In the example of FIGS. 5 a and 5 b, the first unitary valve assembly 11does not actuate as there is no pressure on the spool 80. Therefore, thebore 82 is not pressurized; only the bore 83 is pressurized. Thepressure in the bore 82 causes the spool 81 to lower against the bias ofthe resilient member 69. The fluid entering the inlet passage 35 flowsthrough the inlet port 86, through the outlet port 88, and exits thedouble valve 10 through the outlet passage 40. The second unitary valveassembly 12 in the actuated position couples the outlet passage 40 tothe cross connection passage 55, thereby depressurizing the firstcross-mirror port 92 of the deactuated first unitary valve assembly 11,and fluid flows through the passage 42 to the area under the spool 80.The passage 42 includes a flow restrictor 98 and acts as a monitoringchannel, providing a source of pressure under the spool 80 to maintainthe spool 80 in the deactuated condition. No pressure is provided to thesolenoid pilot valve 13 of the deactuated first unitary valve assembly11, preventing actuation of the first unitary valve assembly 11.However, the double valve 10 can still operate as usual as fluidentering the inlet passage 35 flows through the inlet port 86, throughthe outlet port 88, and exits the double valve 10 through the outletpassage 40. Therefore, a pneumatic press or other equipment operated bythe double valve 10 can continue to be actuated until the maulfunctionin the double valve 10 is corrected. Once the malfunction is discovered(for example, by the use of a pressure switch), the malfunction can becorrected, and the double valve 10 can operate normally.

In the example of FIGS. 6 a and 6 b, the first unitary valve assembly 12does not actuate as there is no pressure on the spool 81. Therefore, thebore 83 is not pressurized; only the bore 82 is pressurized. Thepressure in the bore 83 causes the spool 82 to lower against the bias ofthe resilient member 68. The fluid entering the inlet passage 35 flowsthrough the inlet port 87, through the outlet port 89, and exits thedouble valve through the outlet passage 40. The first unitary valveassembly 11 in the actuated position couples the outlet passage 40 tothe cross connection passage 56, thereby depressurizing the firstcross-mirror port 93 of the deactuated second unitary valve assembly 12,and fluid flows through the passage 43 to the area under the spool 81.The passage 43 includes a flow restrictor 99 and acts as a monitoringchannel, providing a source of pressure under the spool 81 to maintainthe spool 81 in the deactuated position. No pressure is provided to thesolenoid pilot valve 14 of the deactuated second unitary valve assembly12, preventing actuation. However, the double valve 10 can still operateas usual as fluid entering the inlet passage 35 flows through the inletport 87, through the outlet port 79, and exits the double valve 10through the outlet passage 40. Therefore, a pneumatic press or otherequipment operated by the double valve 10 can be actuated until themalfunction in the double valve 10 is corrected. Once the malfunction isdiscovered (for example, by the use of a pressure switch), themalfunction can be corrected and the double valve 10 can operatenormally.

Regardless of the type of malfunction, the double valve 10 continues tooperate as usual during the time of the malfunction, allowing acontinuous source of fluid to flow through the double valve 10.

FIGS. 7 a to 10 b illustrate another double valve 110 including firstand second unitary valve assemblies 111 and 112. The double valve 110includes spools 180 and 181, respectively, received in longitudinalbores 182 and 183, respectively, of valve bodies 184 and 185,respectively. The spools 180 and 181 are inverted relative to eachother. The first and second unitary valve assemblies 111 and 112 areeach 5 port, 2 position valves (5/2-way valves). The first and secondunitary valve assemblies 111 and 112 include inlet ports 186 and 187,respectively, first outlet ports 188 a and 189 a, respectively, secondoutlet ports 188 b and 189 b, exhaust ports 190 and 191, respectively,and ports 194 and 195, respectively. The inlet ports 186 and 187 areinterconnected by an inlet passage 135, the first outlet ports 188 a and189 b are interconnected by a first outlet passage 140 a, the secondoutlet ports 188 b and 189 a are interconnected by a second outletpassage 140 b, and the ports 194 and 195 are interconnected by aconnection passage 155.

The first plate 17 and the second plate 18 for implementing the passages135, 140 a, 140 b and 155 are not explicitly shown to simply thedrawings. The pilot supply for the first unitary valve 111 assembly ispulled from the inlet port 186, and the pilot supply for the secondunitary valve assembly 112 is pulled from the inlet port 187. As thedouble valve 110 includes two outlet passages 140 a and 140 b, fluid canbe directed to two different locations. For example, fluid can bedirected to both ends of a cylinder 154 that requires pressure at bothends.

FIG. 7 a shows the double valve 110 in an initial non-actuated position,and FIG. 7 b shows a schematic representation of the pneumatic circuitsof the double valve 110 in the initial, deactuated position. Bothsolenoid pilot valves 113 and 114 are non-energized. The fluid entersthe inlet passage 135, flows from the inlet port 186 to the port 194,and flows through the connection passage 155 and through the port 195,and flows through the outlet port 189 b and exits the double valve 110through the first outlet passage 140 a. In the initial position, theoutlet passage 140 a is pressurized, and fluid does not flow through theoutlet passage 140 b. As the solenoid pilot valves 113 and 114 are notactuated, fluid does not flow into the bores 182 and 183, and the bores182 and 183 are not pressurized.

In the non-actuated position, the spool 181 blocks the inlet port 187,preventing the flow of fluid through the inlet port 187. Pressurizedfluid enters the double valve 110 through the inlet passage 135, and theinlet ports 186 and 187 provide fluid to inlets of the solenoid pilotvalves 113 and 114, respectively, via passages 196 and 197,respectively. However, as the solenoid pilot valves 113 and 114 are notenergized, fluid does not enter the bores 182 and 183, respectively.Return resilient members 168 and 169 urge the spools 180 and 181,respectively, into the deactuated positions. In one example, theresilient members 168 and 169 are springs. The exhaust ports 190 and 191are coupled to the second outlet ports 189 a and 188 b, respectively.

FIG. 8 a shows the double valve 110 in the actuated position, and FIG. 8b shows a schematic representation of the pneumatic circuits of thedouble valve 110 in the actuated position. Both solenoid pilot valves113 and 114 are energized. The fluid enters the inlet passage 135, flowsfrom the inlet port 187 to the port 195, flows through the connectionpassage 155 to the port 194, and flows to the outlet port 189 a andexits the double valve 110 through the second outlet passage 140 b. Inthe actuated position, the outlet passage 140 b is pressurized, andfluid does not flow through the outlet passage 140 a. As the solenoidpilot valves 113 and 114 are actuated, fluid flows into the bores 182and 183, and the bores 82 and 83 are pressurized.

When the solenoid pilot valves 113 and 114 are actuated, one or moreelectrical switches (not shown) supply a source of pressurized fluid.That is, when the double valve 110 is actuated, both solenoid pilotvalves 113 and 114 are energized, and the passages 196 and 197 arepressurized, allowing the fluid to flow into the bores 182 and 183,moving the spools 180 and 181 to the actuated position against the biasof the resilient members 168 and 169, respectively.

FIGS. 9 a and 10 a show the double valve 10 in an errored and fail tosafe position, and FIGS. 9 b and 10 b show a schematic representation ofthe pneumatic circuits of the double valve 110 in the errored and failto safe position, for example when one of the spools 180 and 181 is notshifting properly. If there is a malfunction, the pressure is releasedfrom the double valve 110.

In FIGS. 9 a and 9 b, the first unitary valve assembly 111 is in theactuated position, and the second unitary valve assembly 112 is in thedeactuated position. In one example, both solenoid pilot valves 113 and114 are actuated, but the spool 180 sticks. This causes the bore 182 tobecome pressurized, actuating the spool 180. However, as the solenoidpilot valve 114 is not actuated, the spool 181 does not move to theactuated position as there is no pressure on the spool 181. The spools180 and 181 block the inlet ports 186 and 187, respectively. Therefore,both outlets 140 a and 140 b are depressurized. Pressurized fluid in thedouble valve 110 in the connection passage 155 either 1) flows throughthe port 194, through the second outlet ports 189 a and 189 b, and exitsthe double valve 191 through the exhaust port 191 or 2) flows throughthe port 195, through the second outlet ports 189 a and 189 b and exitsthe double valve 110 through the exhaust port 191. Fluid can alsoexhaust through the outlet passage 140 a and 140 b. As a result, apneumatic press or other equipment operated by the double valve 110cannot actuate until the malfunction in the double valve 110 iscorrected.

In FIGS. 10 a and 10 b, the first unitary valve assembly 111 is in thedeactuated position, and the second unitary valve assembly 112 is in theactuated position. In one example, both solenoid pilot valves 113 and114 are actuated, but the spool 181 sticks. This causes the bore 183 tobecome pressurized, actuating the spool 181. However, as the solenoidpilot valve 113 is not actuated, the spool 180 does not move to theactuated position as there is no pressure on the spool 180. Therefore,both of the outlet passages 140 a and 140 b are depressurized.Pressurized fluid in the double valve 110 either 1) flows through thesecond outlet ports 189 a and 189 b and exits the double valve 110through the exhaust port 191 or 2) flows through the second outlet ports189 a and 189 b and exits the double valve 110 through the exhaust port191. Fluid can also exhaust through the outlet passages 140 a and 140 b.As a result, a pneumatic press or other equipment operated by the doublevalve 110 cannot be actuated until the malfunction in the double valve110 is corrected.

FIGS. 11 a, 11 b and 12 to 17 illustrate a double valve 210. The firstand second unitary valve assemblies 211 and 212 include spools 280 and281, respectively, received in longitudinal bores 282 and 283,respectively, of valve bodies 284 and 285, respectively. Using FIG. 11 aas a reference, an upper portion 282 a and 283 a of the bores 282 and283, respectively, is located above the spools 280 and 280,respectively, and a lower portion 282 b and 283 b of the bores 282 and283, respectively, is located below the spools 280 and 281,respectively. A resilient member 268 a, 268 b, 269 a and 269 b islocated in each of the portions 282 a, 282 b, 283 a and 283 b,respectively, to provide a force to the respective spool 280 and 281. Inone example, the resilient members 268 a, 268 b, 269 a and 269 b aresprings. The first and second unitary valve assemblies 211 and 212 are 5port, 3 position valves (5/3-way valves).

The double valve 210 includes an inlet port 286 and an exhaust port 287,and the first and second unitary valve assemblies 211 and 212 eachinclude first outlet ports 288 and 289, respectively, second outletports 290 and 291, respectively, first ports 292 and 293, respectively,and second ports 294 and 295, respectively. The first outlet ports 288and 289 are in communication with a first outlet passage 240, and thesecond outlet ports 290 and 291 are in communication with a secondoutlet passage 241. The first ports 292 and 293 are in communicationwith a first passage 255, and the second ports 294 and 295 are incommunication with a second passage 256. The first plate 17 and thesecond plate 18 for implementing the passages 240, 241, 255 and 256 arenot explicitly shown to simply the drawings.

The first unitary valve assembly 211 includes two pilot solenoid valves213 a and 213 b, and the second unitary valve assembly 212 includes twopilot solenoid valves 214 a and 214 b. The spools 280 and 281 aremovable between three positions: a central position, a lowered position,and a raised position. The central position is between the loweredposition and the raised position. The resilient members 268 a, 268 b,269 a and 269 b bias the spools 280 and 281 to the central position. Asthe double valve 210 includes two outlet passages 240 a and 240 b, fluidcan be directed to two different sources. For example, fluid can bedirected to both ends of a cylinder 254 that requires pressure at bothends. An indicator 257 separates the ends of the cylinder 245. Undernormal conditions, the outlet passages 240 and 241 are closed.

FIG. 11 a shows the double valve 210 in an initial position, and FIG. 11b shows a schematic representation of the pneumatic circuits of thedouble valve 210 in the initial position. In the initial position, fluiddoes not flow through the double valve 210. The spools 280 and 281 arein the first central position. The pilot solenoid valves 213 a, 213 b,214 a and 214 b are not energized. The spool 280 and 281 are not in thecentral position, and the pressure is trapped in the outlet passages 240and 241. If there is a malfunction, the pressure is released from thedouble valve 210.

FIG. 12 illustrates the double valve 210 in a first actuated position.The pilot solenoid valves 213 a and 214 b are energized, providingpressure to the bores 282 a and 283 b. Pressurized fluid enters thedouble valve 210 through the inlet port 286 and is provided torespective inlets of the solenoid pilot valves 213 a and 214 b viapassages 296 and 297. The spool 280 is biased from the central positionto the lower position, and the spool 281 is biased from the centralposition to the raised position, compressing the resilient members 268 band 269 a, respectively. The fluid flows from the inlet port 286 to theport 292, through the first passage 255, to the port 293, to the port289 and exits the double valve 210 through the outlet passage 240, whichis pressurized. Air in the second passage 256 is exhausted through theoutlet passage 241, which is non-pressurized.

FIG. 13 illustrates the double valve 210 in a second actuated position.The pilot solenoid valves 213 b and 214 a are energized, providingpressure to the portions 282 b and 283 a. Pressurized fluid enters thedouble valve 210 through the inlet port 286 and is provided torespective inlets of the pilot solenoid valves 213 b and 214 a viapassages 296 and 297, respectively. The spool 280 is biased from thecentral position to the raised position, and the spool 281 is biasedfrom the central position to the lowered position, compressing theresilient members 268 a and 269 b respectively. The fluid flows from theinlet port 286 to the port 294, through the second passage 256, throughthe port 295, through the port 291 and exits the double valve 210through the outlet passage 241, which is pressurized. Air in the firstpassage 255 is exhausted through the outlet passage 240, which isnon-pressurized.

When the signals from the solenoid pilot valves 213 a, 213 b, 214 a and214 b are removed, the spools 280 and 281 should return to the centralposition and trap pressure at the outlets 240 and 241. If a malfunctionoccurs, due to, for example, the incorrect shifting of one of the spools280 and 281, the double valve 210 operates in a closed center position,trapping pressure at both the outlet passages 240 and 241, resulting inno motion of the actuator. Therefore, fluid does not pass through thedouble valve 210.

FIG. 14 illustrates the double valve 210 in an errored and fail to safecondition. The spool 280 is in the lowered position, and the spool 281is in the central position. Fluid enters the inlet port 286 and flows tothe port 292, through the first passage 255, and to the port 293,blocking further flow of the fluid. The pilot solenoid valve 213 a isenergized, providing pressure to the bore 282 a that maintains the spool280 in the lowered position. Pressure is trapped in both of the outletpassages 240 and 241.

FIG. 15 illustrates the double valve 210 in another errored and fail tosafe condition. The spool 280 is in the raised position, and the spool281 is in the central position. Fluid enters the inlet port 286 andflows to the port 294, through the second passage 256, and to the port295, blocking further flow of the fluid. The pilot solenoid valve 213 bis energized, providing pressure to the bore 282 b, maintaining thespool 280 in the raised position. Pressure is trapped in both the outletpassages 240 and 241.

FIG. 16 illustrates the double valve 210 in another errored and fail tosafe condition. The spool 280 is in the central position, and the spool281 is in the lowered position. Fluid enters the inlet port 286 and isblocked from further flow by the spool 280. The pilot solenoid valve 214a is energized, providing pressure to the portion 283 a, maintaining thespool 281 in the lowered position. Pressure is trapped in both theoutlet passages 240 and 241.

FIG. 17 illustrates the double valve 210 in another faulted condition.The spool 280 is in the central position, and the spool 281 is in theraised position. Fluid enters the inlet port 286 and is blocked fromfurther flow by the spool 280. The pilot solenoid valve 214 b isenergized, providing pressure to the chamber 283 b, maintaining thespool 281 in the raised position. Pressure is trapped in both the outletpassages 240 and 241.

FIG. 18 illustrates the double valve 210 in another errored and fail tosafe condition. The spools 280 and 281 are in the lowered position.Fluid enters the inlet port 286 and flows to the port 292 and throughthe first passage 255, blocking further flow of the fluid. When amalfunction occurs, any fluid left in the passage can exhaust throughthe exhaust port 287. The pilot solenoid valves 213 a and 214 a areenergized, providing pressure to the bore 282 a and 2823 a,respectively, maintaining the spools and 280 and 281 in the loweredposition. Pressure is trapped in both the outlet passages 240 and 241.

FIG. 19 illustrates the double valve 210 in another errored and fail tosafe condition. The spools 280 and 281 are in the raised position. Fluidenters the inlet port 286 and flows to the port 294 and through thepassage 256, blocking further flow of the fluid. When a malfunctionoccurs, any fluid left in the passage can exhaust through the exhaustport 287. The spool 281 blocks further flow of the fluid. The pilotsolenoid valves 213 b and 214 b are energized, providing pressure to thebores 282 b and 283 b, respectively, maintaining the spools 280 and 281in the raised position. Pressure is trapped in both the outlet passages240 and 241.

FIGS. 20 a to 23 b illustrate another double valve 310. The first andsecond unitary valve assemblies 311 and 312 each include spools 380 and381, respectively, received in longitudinal bores 382 and 383,respectively, of valve bodies 384 and 385, respectively. Using FIG. 20 aas a reference, a bore 382 is located above the spools 380, and a bore382 is located below the spool 381. A resilient member 368 and 369provides a force to the respective spool 380 and 381 to bias the spools380 and 381, respectively, to an initial condition. In one example, theresilient members 368 and 369 are springs. The first and second unitaryvalve assemblies 311 and 312 are 5 port, 2 position valves (5/2-wayvalves).

The double valve 310 includes an inlet port 386 and an exhaust port 387,and the first and second unitary valve assemblies 311 and 312 includefirst outlet ports 388 and 389, respectively, second outlet ports 390and 391, respectively, first ports 392 and 393, respectively, and secondports 394 and 395, respectively. The first outlet ports 388 and 389 arein communication with a first outlet passage 340, and the second outletports 390 and 391 are in communication with a second outlet passage 341.The first ports 392 and 393 are in communication with a first passage355, and the second ports 394 and 395 are in communication with a secondpassage 356. The first plate 17 and the second plate 18 for implementingthe passages 340, 341, 355 and 356 are not explicitly shown to simplythe drawings.

The unitary valve assembly 211 and 212 includes pilot solenoid valve 313and 314, respectively. The spools 381 and 381 are movable between aninitial position and an actuated position. The resilient members 328 and369 bias the spools 380 and 381 to the initial position. A cylinder 354including an indicator 357 shows the distribution of the pressure. Asthe double valve 310 includes the two outlet passages 340 and 341, fluidcan be directed to two different sources. For example, fluid can bedirected to both ends of a cylinder 354 that requires pressure at bothends. An indicator 357 separates the ends of the cylinder 345. Undernormal conditions, the outlet passages 340 and 341 are closed.

FIG. 20 a shows the double valve 310 in an initial position, and FIG. 20b shows a schematic representation of the pneumatic circuits of thedouble valve 310 in the initial position. In the initial position, thepilot solenoid valves 313 and 314 are not energized. The resilientmembers 368 and 368 bias the spools 380 and 381, respectively, to theinitial position. Pressurized fluid enters the double valve 310 throughthe inlet port 386 and is provided to respective inlets of the solenoidpilot valves 313 and 314 via passages 396 and 397, respectively. Thepressurized fluid enters the double valve 310 through the inlet port386, flows to the second port 394, flows through the second passage 356to the second port 395, flows to the port 391, and exits the doublevalve 310 through the outlet passage 341, which is pressurized. Thenon-pressurized is exhausted through the outlet passage 341. This isreflected in the cylinder 354 and the indicator 357.

FIG. 21 a illustrates the double valve 310 in an actuated position, andFIG. 21 b shows a schematic representation of the pneumatic circuits ofthe double valve 310 in the actuated position. In the actuated position,the pilot solenoid valves 313 and 314 are energized, providing pressureto the bores 382 and 383. Pressurized fluid enters the double valve 310through the inlet port 386 and is provided to respective inlets of thesolenoid pilot valves 313 and 314 via passages 396 and 297,respectively. The inlet port 386 is in communication with both thepassage 296 and 297, respectively, pressurizing the bores 382 and 383,respectively, against the bias of the resilient member 368 and 369,respectively, to the actuated position. The pressurized fluid enters thedouble valve 310 through the inlet port 386, flows to the first port392, flows through the first passage 355 to the first port 393, flows tothe port 389, and exits the double valve 310 through the outlet passage340, which is pressurized. The non-pressurized is exhausted through theoutlet passage 340.

FIG. 22 a illustrates the double valve 310 in an errored and fail tosafe position, and FIG. 22 b shows a schematic representation of thepneumatic circuits of the double valve 310 in the errored and fail tosafe position. The pilot solenoid valve 313 is energized, providingpressure to the bore 382, maintaining the spool 380 in the actuatedposition. The spool 381 is in the initial position. In this position,fluid enters the inlet port 386 and flows to the first port 392, flowsthrough the second passage 356, flows to the first port 393, and flowsto the exhaust port 387, where the fluid is exhausted. Pressure istrapped in both of the outlet passages 340 and 341.

FIG. 23 a illustrates the double valve 310 in another errored and failto safe position, and FIG. 23 b shows a schematic representation of thepneumatic circuits of the double valve 310 in the another errored andfail to safe position. The pilot solenoid valve 314 is energized,providing pressure to the bore 282, maintaining the spool 381 in theactuated position. The spool 380 is in the initial position. In thisposition, fluid enters the inlet port 386 and flows to the second port394, flows through the first passage 355, flows to the second port 395,and flows to the exhaust port 387, wherein the fluid is exhausted.Pressure is trapped in both of the outlet passages 340 and 341.

By employing a valve 110, 210 and 310 with two outlet passages, fluidcan be directed to two sources.

The foregoing description is only exemplary of the principles of theinvention. Many modifications and variations of the present inventionare possible in light of the above teachings. The preferred embodimentsof this invention have been disclosed, however, so that one of ordinaryskill in the art would recognize that certain modifications would comewithin the scope of this invention. It is, therefore, to be understoodthat within the scope of the appended claims, the invention may bepracticed otherwise than as specifically described. For that reason thefollowing claims should be studied to determine the true scope andcontent of this invention.

1. A double valve comprising: a first unitary valve assembly including afirst outlet port, a second outlet port, and a first spool; a secondunitary valve assembly including another first outlet port, anothersecond outlet port and a second spool; a first pilot assembly coupled tothe first unitary valve assembly; a second pilot assembly coupled to thesecond unitary valve assembly; and a plate coupled to the first unitaryvalve assembly and the second unitary valve assembly, the plateincluding respective passages to provide a first common outlet passagecoupled to the first outlet port and the another first outlet port and asecond common outlet passage coupled to the second outlet port and theanother second outlet port; wherein, when the first spool and the secondspool are in a first position, fluid flows through the first commonoutlet passage, and when the first spool and the second spool are in asecond position, the fluid flows through the second common outletpassage.
 2. The double valve as recited in claim 1 wherein the firstunitary valve assembly is inverted relative to the second unitary valveassembly.
 3. The double valve as recited in claim 1 including an inletpassage, wherein the first position is an initial position and thesecond position is an actuated position, and the fluid enters the doublevalve through the inlet passage, wherein the fluid exits the doublevalve through the first common outlet passage when the first spool andthe second spool are in the initial position, and the fluid exits thedouble valve through the second common outlet passage when the firstspool and the second spool are in the actuated position.
 4. The doublevalve as recited in claim 3 including a first solenoid pilot valveassociated with the first unitary valve assembly and a second solenoidpilot valve associated with the second unitary valve assembly, whereinenergization of the first solenoid pilot valve and the second solenoidpilot valve moves the first spool and the second spool, respectively, tothe actuated position.
 5. The double valve as recited in claim 3 whereina first resilient member and a second resilient member biases the firstspool and the second spool, respectively, to the initial position. 6.The double valve as recited in claim 3 wherein, when one of the firstspool and the second spool is in the initial position and the other ofthe first spool and the second spool is in the actuated position, thedouble valve malfunctions, and the fluid does not flow through eitherthe first common outlet passage or the second common outlet passage. 7.The double valve as recited in claim 1 including an inlet passage,wherein the first position is a first actuated position and the secondposition is a second actuated position, the fluid enters the doublevalve through the inlet passage, and the first spool and the secondspool further include a third position located between the firstposition and the second position, wherein the third position is aninitial position, wherein the fluid exits the double valve through thefirst common outlet passage when the first spool and the second spoolare in the first actuated position, and the fluid exits the double valvethrough the second common outlet passage when the first spool and thesecond spool are in the second actuated position, and the fluid does notexit the double valve through either the first common outlet passage orthe second common outlet passage when the first spool and the secondspool are in the initial position.
 8. The double valve as recited inclaim 7 including a first solenoid pilot valve and another firstsolenoid pilot valve associated with the first unitary valve assemblyand a second solenoid pilot valve and another second solenoid pilotvalve associated with the second unitary valve assembly, whereinenergization of the first solenoid pilot valve and the another secondsolenoid pivot valve moves the first spool and the second spool to thefirst actuated position, and energization of the another first solenoidpilot valve and the second solenoid pivot valve moves the first spooland the second spool to the second actuated position.
 9. The doublevalve as recited in claim 7 wherein a first resilient member and asecond resilient member biases the first spool and the second spool,respectively, to the initial position.
 10. The double valve as recitedin claim 7 wherein, when one of the first spool and the second spool isin the initial position and the other of the first spool and the secondspool is in one of the first actuated position and the second actuatedposition, the double valve malfunctions, and the fluid does not exit thedouble valve through either the first common passage or the secondcommon outlet passage.
 11. The double valve as recited in claim 7wherein, when one of the first spool and the second spool is in one ofthe first actuated position and the second actuated position, and theother of the first spool and the second spool is in the other of thefirst actuated position and the second actuated position the doublevalve malfunctions, and the fluid does not exit the double valve througheither the first common outlet passage or the second common outletpassage.
 12. A pneumatically powered machine tool comprising: a cylinderincluding a first end and a second end; and a double valve including afirst unitary valve assembly including a first outlet port, a secondoutlet port, and a first spool, a second unitary valve assemblyincluding another first outlet port, another second outlet port and asecond spool, a first pilot assembly coupled to the first unitary valveassembly, a second pilot assembly coupled to the second unitary valveassembly, and a plate coupled to the first unitary valve assembly andthe second unitary valve assembly, the plate including respectivepassages to provide a first common outlet passage coupled to the firstoutlet port and the another first outlet port and a second common outletpassage coupled to the second outlet port and the another second outletport, wherein, when the first spool and the second spool are in a firstposition, fluid flows through the first common outlet passage to thefirst end of the cylinder, and when the first spool and the second spoolare in a second position, the fluid flows through the second commonoutlet passage to the second end of the cylinder.
 13. The double valveas recited in claim 12 including an inlet passage, wherein the firstposition is an initial position and the second position is an actuatedposition, and the fluid enters the double valve through the inletpassage, wherein the fluid exits the double valve through the firstcommon outlet passage when the first spool and the second spool are inthe initial position, and the fluid exits the double valve through thesecond common outlet passage when the first spool and the second spoolare in the actuated position.
 14. The double valve as recited in claim13 including a first solenoid pilot valve associated with the firstunitary valve assembly and a second solenoid pilot valve associated withthe second unitary valve assembly, wherein energization of the firstsolenoid pilot valve and the second solenoid pilot valve moves the firstspool and the second spool, respectively, to the actuated position. 15.The double valve as recited in claim 13 wherein, when one of the firstspool and the second spool is in the initial position and the other ofthe first spool and the second spool is in the actuated position, thedouble valve malfunctions, and the fluid does not flow through eitherthe first common outlet passage or the second common outlet passage. 16.The double valve as recited in claim 12 including an inlet passage,wherein the first position is a first actuated position and the secondposition is a second actuated position, the fluid enters the doublevalve through the inlet passage, and the first spool and the secondspool further include a third position located between the firstposition and the second position, wherein the third position is aninitial position, wherein fluid exits the double valve through the firstcommon outlet passage when the first spool and the second spool are inthe first actuated position, and the fluid exits the double valvethrough the second common outlet passage when the first spool and thesecond spool are in the second actuated position, and the fluid does notexit the double valve through either the first common outlet passage orthe second common outlet passage when the first spool and the secondspool are in the initial position.
 17. The double valve as recited inclaim 16 including a first solenoid pilot valve and another firstsolenoid pilot valve associated with the first unitary valve assemblyand a second solenoid pilot valve and another second solenoid pilotvalve associated with the second unitary valve assembly, whereinenergization of the first solenoid pilot valve and the another secondsolenoid pivot valve moves the first spool and the second spool to thefirst actuated position, and energization of the another first solenoidpilot valve and the second solenoid pivot valve moves the first spooland the second spool to the second actuated position.
 18. The doublevalve as recited in claim 16 wherein, when one of the first spool andthe second spool is in the initial position and the other of the firstspool and the second spool is in one of the first actuated position andthe second actuated position the double valve malfunctions, and thefluid does not exit the double valve through either the first commonoutlet passage or the second common outlet passage.
 19. The double valveas recited in claim 16 wherein, when one of the first spool and thesecond spool is in one of the first actuated position and the secondactuated position and the other of the first spool and the second spoolis in the other of the first actuated position and the second actuatedposition the double valve malfunctions, and the fluid does not exit thedouble valve through either the first common outlet passage or thesecond common outlet passage.